Investment costs of the system can be different from case to case. Cost of the collector array depends on the several conditions e.g. location, size of the system (ranging between 600 and 200 € per m²) and can be related to the solar heat gains in kWh per m².
Quotient of these values multiplied with an annuity factor gives the cost of the solar heat (Example: 300 €/m² and 400 kWh/m² and annuity factor 0.08 gives a price 0.06 €/kWh) Cost of the heat storage varies depending on the system design from very low if the collector array is connected directly to the district heating network without storage to about doubling the investment cost in € per m² when long term storage is used. An online calculation tool is available for free at: